386 Darwin, and after Darwin. 
battle, in fact, more nearly approaches the law of 
natural selection; seeing that it expresses the natural 
advantages of brute force in the struggling of rival 
animals, and so frequently results in death of the less 
| fitted, as distinguished from a mere failure to propa- 
_ gate. Now against this doctrine of the law of battle, 
and the consequences to which it leads in the superior 
fighting powers of male animals, no objection has 
been raised in any quarter. It is only with regard to 
the other aspect of the theory of sexual selection— 
or that which is concerned with the superior em- 
bellishment of male animals—that any difference of 
opinion obtains. I will now proceed to give the 
main arguments on both sides of this question, 
beginning with a résemé of the evidences in favour of 
sexual selection. 
In the first place, the fact that secondary sexual 
characters of the embellishing kind are so generally 
restricted to the male sex in itself seems to constitute 
very cogent proof that, in some way or another, such 
characters are connected with the part which is played 
by the male in the act of propagation. Moreover, 
secondary sexual characters of this kind are of quite 
as general occurrence as are those of the other kind 
which have to do with rivalry in battle ; and the former 
are usually of the more elaborate description. There- 
fore, as there is no doubt that secondary sexual char- 
acters of the one order have an immediate purpose to 
serve in the act of propagation, we are by this close 
analogy confirmed in our surmise that secondary sexual 
characters of the other, and still more elaborate, order 
are likewisc so concerned. Moreover, this view of their 
meaning becomes still further strengthened when we 
